Black Hole Mass and Eddington Ratio as Drivers for the Observable Properties of Radio‐loud and Radio‐quiet QSOs

Recent studies of black holes in the nuclei of both active and normalgalaxies have yielded relationships that permit a physical interpretation ofthe principal components of the spectra of QSOs. It is shown that principalcomponent (or eigenvector) 1 (PC1) is driven predominantly by L/L{Edd}, andprincipal component 2 (PC2) is driven by luminosity or accretion rate. Thisresults in a PC2 vs. PC1 diagram in which lines of constant black hole mass arediagonal. Using a sample consisting of the low-redshift PG objects supplementedby 46 radio-loud QSOs, it is shown that such a diagram effectivelydistinguishes radio-loud from radio-quiet as well as demonstrating that bothnarrow-line Seyfert 1s and broad absorption-line QSOs (BALQSOs) lie at the highL/LEdd} extreme, though these two types of objects are well separated in thePC2 direction. The very few radio-loud BALQSOs known fall in the regionexpected to be populated by such objects. Finally, a simple picture that tiestogether physical parameters and classification of AGN is presented.Comment: 21 pages including 7 figures, accepted for publication in Ap.